This invention relates to open end spinning wherein a vacuum is required to carry on the spinning operation. Vacuum pressure is employed to draw fibers from the opening roll into the spinning rotor and to remove trash, such as leaves, twigs, husks, seeds, dirt and other extraneous materials from the fibers in well-known operations. Separate vacuum sources are usually employed for these operations, but a single source may be used, as disclosed in my copending patent application Ser. No. 578,352 filed on May 16, 1975. The vacuum source, or sources, is connected to a plurality of spinning units, so that if the vacuum is interrupted, or if the vacuum pressure is substantially reduced, all of the spinning units connected thereto are affected. Interruption of the vacuum at the spinning rotor will stop the spinning operation and break the thread being produced. This makes necessary the piecing-up of the thread and restarting the spinning operation at each of the plurality (often about 100) of spinning stations affected. A substantial reduction in vacuum pressure at the spinning rotor will change the quality of the thread being produced, which is unacceptable. Interruption or reduction of vacuum pressure to the cleaning chamber would permit the trash to enter the spinning apparatus, where it could stop the passage of fibers to the spinning rotor, stopping the spinning operation and breaking the thread, or it could be incorporated in the spun thread, producing a defect, which would be unacceptable.
In the past large filters have been used to separate the trash from the air stream near the vacuum source to prevent its entrance into the vacuum producing apparatus or its discharge into the atmosphere. Before these filters become sufficiently clogged to substantially reduce the vacuum pressures in the spinning and cleaning chambers, the spinning machines were shut-off, the vacuum producing apparatus was stopped, the filter chamber was opened and the trash manually scraped from the filter and removed from the filter chamber, after which the filter chamber was closed, the vacuum producing apparatus started, the spinning machines turned-on, and at each of the plurality of spinning units the thread was pieced-up and spinning restarted. This consumed a great amount of time, resulting in increased labor cost and decreased thread production.